An actuator is provided with a tubular actuator element and a supporting body which supports an inner peripheral surface of the actuator element. An internal pressure of the actuator element is higher than an external pressure of the actuator element.

A variable stiffening device that includes a flexible envelope having a fluid chamber, a dielectric fluid housed within the fluid chamber, and an electrode stack that includes a plurality of electrodes and one or more abrasive strips. The electrode stack is housed within the fluid chamber and is configured to receive voltage. In addition, the one or more abrasive strips are each positioned between adjacent electrodes, such that when voltage is applied to the electrode stack thereby electrostatically drawing adjacent electrodes together, the one or more abrasive strips generate frictional engagement between adjacent electrodes to actuate the variable stiffening device from a relaxed state to a rigid state.

A MEMS electrostatic piston-tube actuator is disclosed. The actuator comprises two structures. A structure that comprises a plurality of fixed piston-like electrodes that are attached to a base, and form the stator of the actuator. A second structure that comprises a plurality of moving tube-like electrodes that are attached to the body of the upper structure and form the rotor of the actuator. The rotor is attached to the stator through a mechanical spring. The rotor of the actuator provides a translational motion, about the normal axis to the structures. The present piston-tube actuator utilizes a configuration that enables the use of wide area electrodes, and therefore, provides a high output force enabling translation of the rotor.

In an example, a method includes interacting electric fields from charges in conductors in different inertial reference frames to effect motion. The example method implements the mathematical framework that divides electric fields from charges in different inertial reference frames into separate electric field equations in electrically isolated conductors. The example method may implement the interaction of these electric fields to produce a force on an assembly that can, by way of illustration, propel a spacecraft using electricity without other propellant(s).

A high-voltage electrostatic generator has an assembly of concentric electrically conductive half-shells separated by an equatorial gap, essentially with cylindrical symmetry about an axis. Adjacent to the equatorial gap, edge regions of at least a selected subset of the half-shells are shaped.

An electronic watch includes a power source, an electrostatic motor including a rotor in which a plurality of electret films are arranged in a rotational direction and a plurality of fixed electrodes arranged in the rotational direction at positions facing the rotor, a hand rotating in conjunction with the rotation of the rotor, and a motor control circuit controlling the electrostatic motor. The motor control circuit selectively executes a hand movement mode for rotating the hand and a stop mode for keeping the hand stationary. In the stop mode, the motor control circuit keeps the rotor stationary through electrostatic forces exerted on the electret films from the fixed electrodes with the polarities of the fixed electrodes maintained.

Caging structures are disclosed for caging or otherwise reducing the mechanical shock pulse experienced by MEMS device beam structures during events that may cause mechanical shock to the MEMS device. The caging structures at least partially surround the beam such that they limit the motion of the beam in a direction perpendicular to the beam's longitudinal axis, thereby reducing stress on the beam during a mechanical shock event. The caging structures may be used in combination with mechanical shock-resistant beams.

A variable stiffening device that include a first electrode structure and a second electrode structure. The first electrode structure includes an electrode extension that extends into a cavity defined between an electrode of the first electrode structure and an opposing electrode of the second electrode structure. The first and second electrode structures may be arranged in a load-bearing state by applying a voltage thereto to electrostatically attract the electrode to the opposing electrode to press the electrode extension within the cavity. Friction between the electrode extension and engaging surfaces defining the cavity prevent the electrode extension from slipping within the cavity, thereby maintaining a structural relationship among the components of the first and second electrode structures in response to an application of a load to the variable stiffening device.

A comb drive for MEMS device includes a stator and a rotor displaceable relative to the stator in a first direction. The stator includes stator comb fingers and the rotor includes rotor comb fingers. The stator comb fingers are coupled to two high impedance nodes to form high impedance node domains arranged in the first direction. The rotor comb fingers are coupled to two oppositely biased electrodes to form oppositely biased domains. Pairs of capacitors with opposite acoustic polarity are respectively formed between the high impedance node domains and the oppositely biased domains. The comb drive of the present invention has increased electrostatic sensitivity for a given unit cell cross-sectional area whilst maintaining an acceptable capacitance and linearity of voltage signal vs displacement. Extra force shim unit cells may be used, which allows for the stiffness between the rotor and stator to be controlled and reduced to zero for a particular displacement range, without impacting sensitivity.

An electrostatic rotating electrical machine employs axially extending electrically conductive electrodes on a rotor interacting with a corresponding set of axially extending electrodes on a stator, where the electrodes are supported at an outer surface of a dielectric sleeve which continues beneath the electrodes to provide a robust support and to minimize electrode weight.